Tower and wind turbine generator having the same

ABSTRACT

Provided are a tower that has a sufficient yield strength and enables connection between tower sections without requiring a high manufacturing accuracy of the tower sections, and a wind turbine generator having the tower. The tower includes a plurality of tower sections formed by dividing the tower along planes that are parallel to a horizontal plane, and is constituted by connecting end surfaces of the tower sections to each other. The tower further includes a tensile member that has one end supported by a first supporting part at a first tower section among the tower sections, has another end supported by a second supporting part at a second tower section among the tower sections or at a tower base on which the tower is vertically installed, and is stretched along an inner wall of the tower sections so as to have a predetermined tensile force.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a tower and a wind turbine generator having the tower.

2. Description of Related Art

Generally, for example, a tower in a wind turbine generator or the like is constructed by stacking and connecting a plurality of tubular tower sections in the vertical direction on a construction site. This is because a tower having several tens of meters in length is used for such a wind turbine generator, and thus it is difficult to transport a completed tower to a construction site. For this reason, the tower is transported to the construction site in a state in which the tower is divided into the tower sections of transportable sizes.

Generally, as disclosed in PCT International Publication No. WO 2009/028092 A1 (hereinafter referred to as “Patent Literature 1”), an axial end of each tower section has a flange, and a tower is constructed by joining the flanges to each other by use of a plurality of bolts. Alternatively, the specification of U.S. Patent Application Publication No. US 2008/0041009 A1 (hereinafter referred to as “Patent Literature 2”) proposes that wall surfaces of tower sections are connected to each other by friction joint.

BRIEF SUMMARY OF THE INVENTION

The present inventor found the following problems and the objects to be achieved in the inventions disclosed in Patent Literature 1 and Patent Literature 2.

The present inventor found, in Patent Literature 1, a problem that further improvement in the yield strength of a flange junction cannot be expected, and it has become difficult to meet a required yield strength. When receiving a wind force or the like, the tower is bent, applying a load on a member that keeps binding at the junction between the tower sections. Although the yield strength required to address the load increases with an increase in size of the wind turbine generator, it is difficult to make the outer diameter of the tower larger than the existing sizes due to limitations upon transport. Under such a situation, in the case of a flange joint as disclosed in Patent Literature 1, the outer diameter of the flange is also limited by the outer diameter of the tower having transport limitations, and thus it is difficult to increase the number of bolts arranged at the flange. As a result, further improvement in the yield strength of the flange junction cannot be expected, and it has become difficult to meet a required yield strength.

Further, the present inventor found, in Patent Literature 2, problems that a high assembling accuracy is required to connect the tower sections and that a high manufacturing accuracy of the tower section is required to sufficiently reduce misalignment between the butted tower sections, thereby greatly increasing manufacturing costs of the tower. A high assembling accuracy is needed to directly connect wall surfaces configuring the outer shapes of the tower sections with each other and vertically install the tower sections into a vertical tower. In addition, the cylindrical tower section is molded by rounding and joining a steel plate, and according to this manufacturing method, it is difficult to make the sectional shape of the tower section into a perfect circle. When the upper and lower tower sections each having a cross section of an imperfect circle are butted each other, misalignment between the tower sections is easy to be generated. A high manufacturing accuracy is needed to sufficiently reduce such misalignment. Accordingly, implementation of the invention described in Patent Literature 2 leads to a significant increase in costs.

The present inventor also found an object of achieving a connection structure for the tower sections, which has a yield strength necessary for the junction between the tower sections while increasing the wind turbine in size, without leading to a significant increase in costs.

The present invention has been made in consideration of the above-mentioned situations, and an object thereof is to provide a tower having a configuration that has a sufficient yield strength and enables connection between tower sections without requiring a high manufacturing accuracy of the tower sections, as well as to provide a wind turbine generator having the tower.

To solve the problems, the present invention adopts the following solutions.

A tower according to the present invention includes a plurality of tower sections formed by dividing the tower along a plurality of planes that are substantially parallel to a horizontal plane, and is constituted by connecting end surfaces of the tower sections to each other. The tower further includes a tensile member that has one end supported by a first supporting part arranged at a first tower section among the plurality of tower sections, that has another end supported by a second supporting part arranged at a second tower section among the plurality of tower sections or at a tower base on which the tower is vertically installed, and that is stretched along an inner wall of the tower section so as to have a predetermined tensile force.

Since the tensile member is provided that has the one end supported by the first supporting part arranged at the first tower section and the other end supported by the second supporting part arranged at the second tower section or at the tower base on which the tower is vertically installed, when an external force such as a wind force or an earthquake force is applied to the tower, a bending moment applied to the tower generates a tensile force of the tensile member. By applying a part of the force caused by the bending moment on the tensile member, the yield strength at the junction can be improved. Therefore, the load applied on the tower body can be reduced.

Further, since the tensile member is stretched along the inner wall of the tower section, the section modulus of the tensile member against the bending moment generated in the tower can be maximized. Furthermore, by arranging the tensile member in this manner, installation and inspection of the tensile member can be performed inside the tower. Accordingly, the operation at a high place outside the tower is not required, which reduces risks and costs of the operation.

In the case where one or more tower sections are provided between the first tower section and the second tower section or the tower base, the number of supporting parts necessary for binding the tower sections to each other, or binding the tower section to the tower base can be minimized, so that manufacturing and construction costs of the tower can be reduced.

Moreover, since the tensile member is stretched between the tower sections with a predetermined tensile force being applied, a drag force is applied to the end of each of the vertically butted tower sections. A frictional force is generated at the ends of the tower sections by this drag force and can resist an external force component in a plane including the ends of the tower sections.

According to the above-mentioned invention, the tensile member is preferably a wire rope.

When the wire rope is used as the tensile member, construction performance is improved and maintenance work is reduced. By using the wire rope having a higher tensile strength (tensile strength of 1320 to 1770 N/mm²) than that of a high-tensile bolt (tensile strength of 1000 to 1200 N/mm²), the yield strength of the junction can be improved. This improvement of the yield strength at the junction enables reduction of the diameter of the tower, and therefore manufacturing and construction costs of the tower can be reduced. Moreover, since the wire rope is a long tensile member having excellent distributability and transportability, construction costs of the tower using the wire rope can be reduced.

According to the present invention, each of the end surfaces of the tower sections may serve as a flange surface of an inner flange protruding toward the center in cross section of the tower section, a shearing bolt or a shearing key may be fitted into each of a plurality of holes formed substantially vertically in the flange surface, and relative positions between the flanges may be restricted.

When the shearing bolt or the shearing key is fitted into each of the plurality of holes formed in the flange surface, the yield strength against an external force component in the plane including the end surfaces of the tower sections can be improved, and the positions of the ends of the tower sections can be reliably fixed.

According to the present invention, a mechanism adapted to adjust an axial length of the tensile member may be provided at a middle of the tensile member.

By providing the mechanism adapted to adjust the axial length of the tensile member, a strain of the tensile member stretched between two supporting parts can be adjusted. That is, since the tensile force of the tensile member can be adjusted, even when the distance between the first supporting part and the second supporting part varies in a manufacturing or construction stage of the tower section, the tensile force of the tensile member can be set to a desired strength.

Since the tower sections are bound to each other by way of the tensile member stretched between the supporting parts, even when the tower sections have some tolerances, by adjusting the tensile force of the tensile member, the tensile member can be stretched with a predetermined tensile force. For this reason, a high manufacturing accuracy is not required to the tower section, thereby enabling reduction of manufacturing and construction costs of the tower.

According to the present invention, the tensile member may be stretched in a substantially vertical direction, at least one of the first supporting part and the second supporting part may include a groove or a through hole into which the tensile member is inserted, a socket is fixedly attached to an end of the tensile member, which corresponds to the groove or the through hole, and the socket may be locked to the supporting part, thereby restricting displacement with respect to the supporting part.

By providing the groove or the through hole into which the tensile member is inserted in the supporting part, the socket can be easily locked to the supporting part. That is, by making the shape and the size of the socket that cannot pass through the groove or the through hole when the tensile force is generated in the tensile member, the socket can be firmly locked to the supporting part.

Although the socket provided at the end of the tensile member is locked to the supporting part, when no tensile force is generated in the tensile member or the applied tensile force is small, locking between the supporting part and the socket can be easily released by using the groove or the through hole.

According to the present invention, the socket may include a mechanism adapted to adjust relative positions between the socket and the supporting part.

By providing the mechanism adapted to adjust the relative position with respect to the supporting part, the extension distance of the tensile member can be adjusted. That is, since the tensile force of the tensile member can be adjusted, even when the distance between the first supporting part and the second supporting part varies in a manufacturing or construction stage of the tower section, the tensile force of the tensile member can be set to a desired strength.

Since the tower sections are bound to each other by way of the tensile member stretched between the supporting parts, even when the tower sections have some tolerances, by adjusting the tensile force of the tensile member, the tensile member can be stretched with a predetermined tensile force. For this reason, a high manufacturing accuracy is not required to the tower section, thereby enabling reduction of manufacturing and construction costs of the tower.

The first supporting part and/or the second supporting part may include a first member located on a side where the socket is arranged and a second member located on the opposite side to the socket with the first member being interposed therebetween, and the second member may support the first member and be connected to an inner wall surface of the tower section.

The tensile force of the tensile member is applied to the first member through the socket. The first member is supported by the second member provided on the opposite side to the position where the socket is provided, in other words, the side where the tensile member is stretched. Further, since the second member is connected to the tower section, the load applied to the first member can be transmitted to the tower section due to the tensile force of the tensile member.

The present invention may provide a wind turbine generator including the tower according to the present invention.

Since the wind turbine generator including the tower according to the above-mentioned invention can improve the yield strength at the junction, it is possible to realize a wind turbine generator having a rotation axis of a wind turbine blade at a high position from the ground. Since such a wind turbine generator can use a large-sized wind turbine blade and make use of a wind force having a faster wind speed than a wind force in the vicinity of the ground, power of a larger amount can be obtained.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is a side view showing a schematic configuration of an entire wind turbine generator.

FIG. 2 is a vertical sectional view showing arrangement of tensile members in accordance with a first embodiment, and a junction of vertically adjacent tower sections.

FIG. 3 is an X-X sectional view of the tower section shown in FIG. 2.

FIG. 4 is a partial enlarged plan view showing details of a fixing bracket in accordance with the first embodiment.

FIG. 5 is a bottom view showing the fixing bracket in FIG. 4.

FIG. 6 is a Y-Y sectional view showing the fixing bracket in FIG. 5.

FIG. 7 is a partial enlarged plan view showing details of a fixing bracket in accordance with a second embodiment.

FIG. 8 is a bottom view of the fixing bracket in FIG. 7.

FIG. 9 is a partial enlarged plan view showing details of a fixing bracket in accordance with a third embodiment;

FIG. 10 is a bottom view of the fixing bracket in FIG. 9.

FIG. 11 is a partial enlarged plan view showing details of a fixing bracket in accordance with a fourth embodiment.

FIG. 12 is a P-P sectional view of the fixing bracket in

FIG. 11.

FIG. 13 is a side sectional view showing details of a fixing bracket in accordance with a fifth embodiment.

FIG. 14 is a side sectional view of a fixing bracket in accordance with a sixth embodiment.

FIG. 15A is a side sectional view of a fixing bracket in accordance with a seventh embodiment.

FIG. 15B is a plan view of the fixing bracket in the seventh embodiment.

FIG. 16 is a side view of a wire jack in accordance with an eighth embodiment.

FIG. 17A is a plan view showing arrangement of tensile members in a tower in accordance with a ninth embodiment.

FIG. 17B is a vertical sectional view showing arrangement of the tensile members in the tower in accordance with the ninth embodiment.

FIG. 18 is a vertical sectional view showing arrangement of tensile members in a tower in accordance with a tenth embodiment.

DETAILED DESCRIPTION OF THE INVENTION

Using a tower used for a wind turbine generator as an example, one embodiment of a tower according to the present invention will be described with reference to the drawings.

First Embodiment

As shown in FIG. 1, a wind turbine generator 1 includes a tower 3 vertically installed on a base B, a nacelle 6 installed at an upper end of the tower 3, and a rotor head 4 provided at the nacelle 6 so as to be rotatable about a substantially horizontal axis. A plurality of (for example, three) wind turbine rotary blades 5 are radially attached to the rotor head 4 around the rotation axis of the rotor head 4. Thereby the force of the wind on the wind turbine rotary blades 5 from the direction of the rotation axis of the rotor head 4 is converted into power for rotating the rotor head 4 about the rotation axis.

In the first embodiment of the present invention, the tower 3 is configured by stacking and joining a plurality of tower sections 2 to each other in the vertical direction, and is provided in the wind turbine generator 1.

As shown in FIG. 2, a flange 10 is provided at an end of the tower section 2, and at a junction where the ends of the tower sections 2 are butted and joined to each other, the paired flanges 10 are located to be opposed to each other. The paired flanges receive the load of the wind turbine generator that is located above the junction. That is, the flange 10 has a flange surface, and receives, by surface contact, the load applied by the weight of the tower section 2, the nacelle 6, the wind turbine blades 5, and the like, which are located above the junction. A plurality of shearing bolts 8 are provided to the flange 10 so as to be spaced apart from each other at predetermined intervals in the circumferential direction of the flange 10. These shearing bolts 8 are provided inside the tower section 2. Each shearing bolt 8 prevents misalignment in the lateral direction between the vertically adjacent flanges 10 (in-plane direction of the flange surface, which is substantially orthogonal to the axial of the tower) and does not bear mainly a force of separating the vertically adjacent flanges 10 from each other (drawing force). As to be described below, mainly wire ropes (tensile members) bear the drawing force. To prevent lateral misalignment between the flanges 10, in addition to use of the shearing bolts 8 or shearing keys, a method of inserting a member between the opposed flanges 10 to increase a frictional force acting between the flanges 10, or a method of providing irregularity on the flange surface may be employed.

The plurality of wire ropes 14 are provided along the inner wall of the tower section 2 so as to be spaced apart from each other at predetermined intervals in the circumferential direction. One upper end of each wire rope 14 is supported by a fixing bracket (supporting part) 12 arranged at the upper tower section 2, and another lower end of the wire rope 14 is supported by the fixing bracket 12 arranged at the lower tower section 2. A socket 16 is attached to each end of the wire rope 14, and by locking each socket 16 with the fixing bracket 12, the wire rope 14 is stretched between the fixing brackets 12. In this manner, the vertically adjacent tower sections 2 are bound to each other by way of the wire rope 14.

Further, by interposing a shim (not shown) between the socket 16 and the fixing bracket 12, the both ends of the wire rope 14 are supported with a predetermined tensile force being applied to the wire rope 14. Examples of another method of applying the predetermined tensile force to the wire rope 14 include a method of applying the tensile force to the wire rope 14 by providing a screw part at the socket 16 and adjusting the position of the socket 16 by use of the screw part, and a method of applying the tensile force to the wire rope 14 by providing a jack at a middle of the wire rope 14.

FIG. 3 shows an X-X cross section in FIG. 2. As shown in this figure, in the present embodiment, the fixing brackets 12 are provided at four positions and the tower sections 2 are bound to each other by use of the four wire ropes 14. The number of wire ropes 14 can be appropriately changed according to a required strength. The sockets 16 are locked with the fixing bracket 12 that is fixed to the inner side of the tower section 2 so that the wire rope 14 is arranged on the inner circumferential side of the flange 10 provided at the tower section 2. Accordingly, joining by use of the wire rope 14 and joining by use of the bolts at the flanges 10 can be utilized.

FIG. 4 shows one fixing bracket 12 in a plan view. A substantially rectangular bracket platform (first member) 12 c provided to the fixing bracket 12 is fixedly attached to an inner circumferential wall of the cylindrical tower section 2. The wire rope 14 is arranged through a through hole (not shown) formed in the bracket platform 12 c. The wire rope 14 is fixed to the socket 16 by inserting the end of the wire rope 14 thereinto and brining the end into close contact with the socket with a compressive force. The socket 16 is larger than the through hole and can lock the wire rope 14 with the bracket platform 12 c.

FIG. 5 shows the fixing bracket 12 in a bottom view. Two ribs (second members) 12 a which each have one end fixedly attached to an inner circumferential wall surface of the tower section 2 and extend inward in the substantially radial direction, and two ribs (second members) 12 b which are fixedly attached to the two ribs 12 a so as to be substantially perpendicular to the two ribs 12 a, respectively, are provided on a lower surface of the bracket platform 12 c of the fixing bracket 12. The two ribs 12 a and the two ribs 12 b are fixedly attached to the bracket platform 12 c, so that the fixing bracket 12 is integrally fixed to the tower section 2.

FIG. 6 shows a Y-Y cross section in FIG. 5. Since the fixing bracket 12 has a sufficient strength against the tensile force of the wire rope 14, which is applied by way of the socket 16, the above-mentioned ribs 12 a extending along the axis of the wire rope 14 are fixedly attached to the tower section 2 in addition to the bracket platform 12 c.

The ribs 12 a and the ribs 12 b are fixedly attached to the surface of the bracket platform 12 c on the opposite side of the surface with which the socket is locked.

With the above-mentioned configuration, the present embodiment has the following effects.

Since the wire rope 14 that has one end supported by the fixing bracket 12 arranged at the first tower section 2 and another end supported at the second tower section 2 is arranged, in other words, the wire rope 14 is arranged so as to pass through the connection surface as a plane including the end surfaces of the butted tower sections 2 to fix the tower sections 2 to each other, when an external force such as a force of wind, earthquake, or the like is applied to the tower 3, a bending moment applied to the tower 3 generates a tensile force in the wire rope 14. By applying a part of the force caused by the bending moment on the wire rope 14 in this manner, the yield strength of the junction can be improved. Then, the load applied on a body of the tower 3 can be reduced.

Since the tensile strength of the wire rope 14 is larger than that of a high-tensile bolt, as compared to the case where the flanges 10 are joined to each other by use of the bolts, the yield strength of the flanges 10 can be further improved.

Moreover, since both the ends of the wire rope 14 are supported by the fixing bracket 12 with the tensile force being previously applied thereon, a drag force is generated that is orthogonal to the plane including the ends of the butted tower sections 2. Due to this drag force, a frictional force is generated at the flange surfaces of the flanges 10 at the ends of the tower sections 2, thereby resisting an external force component in the plane including the flange surfaces.

Normal inspection of the wire rope 14 may be performed as appearance inspection, and thus an inspection operation is simplified.

Although the end of the wire rope 14 is locked with the fixing bracket 12 by use of the socket 16 in the present embodiment, the end of the wire rope 14 may be single lock processed, grip processed, eye splice processed, or TOYO LOK processed, so as to be locked with the fixing bracket 12.

While the wire rope 14 receives the bending moment generated in the tower 3 as described above, because the flanges 10 at the ends of the tower sections 2 are joined to each other by use of the shearing bolts 8, the yield strength against an external force component in the plane including the flange surfaces can be improved and the positions of the flanges 10 can be fixed further firmly. As described above, the configuration in which the wire rope 14 receives the bending moment generated in the tower 3 and the configuration in which the flanges 10 are joined to each other by use of the bolts can be used in combination. Such combined use can improve the yield strength at the junction.

Since a larger bending moment is applied to a lower junction in the tower, such as the junction between the tower section 2 c and the tower section 2 d (refer to FIG. 1), joining by the wire rope 14 or combination of joining by the wire rope 14 and joining by the bolts at the flanges 10 can be performed. On the other hand, since a smaller bending moment is applied to an upper junction in the tower, such as the junction between the tower section 2 a and the tower section 2 b (refer to FIG. 1), the tower 3 can be connected by either joining by the wire rope 14 or joining by the bolts at the flanges 10. By considering the necessity of the combined use of joining by the wire rope 14 and joining by the bolts or joining by the wire rope 14 according to the yield strength necessary for each junction, and then, selecting a proper joining method, manufacturing and construction costs of the tower 3 can be reduced.

According to the connecting method in the present embodiment, the vertically adjacent tower sections 2 are bound to each other by way of the wire rope 14 stretching between the fixing brackets 12. Even when the tower sections 2 have some tolerances, by adjusting the position where the ends of the wire rope 14 are locked with the tower sections 2, the wire rope 14 can be stretched with a predetermined tensile force. As a result, manufacturing costs of the tower 3 can be reduced without requiring a high manufacturing accuracy of the tower section 2.

Since the wire rope 14 is arranged on the inner wall of the tower section 2, an installing operation of the wire rope 14 can be performed inside the tower 3 with no need of an operation at a high place outside the tower. Further, by arranging the wire rope 14 along the inner wall of the tower section 2 and separating the wire rope 14 from the center in cross section of the tower 3, a large sectional secondary moment generated when the tower 3 is bent can be ensured. The configuration in which the wire rope is arranged along the inner wall of the tower section 2 may be the configuration in which the wire rope is fixed so as to be in contact with the tower section 2, or the configuration in which the wire rope 14 is indirectly fixed to the tower section 2 with the fixing brackets 12 being interposed therebetween at a position separate from the tower section, in order to, for example, avoid any structure in which the wire rope 14 is provided on the inner wall of the tower section 2.

By welding the bracket platform 12 c to the inner wall of the tower section 2 and also to the ribs 12 a welded to the inner wall of the tower section 2, as compared to the case where only the bracket platform 12 c is welded to the tower section 2, the fixing bracket 12 is welded to the tower section 2 in a wider range, resulting in firm fixation. Further, when the tensile force is applied to the wire rope 14, a large sectional secondary moment of the fixing bracket 12, which is effective for the bending moment applied to the fixing bracket 12, can be ensured, thereby reliably locking the wire rope 14 by way of the socket 16.

Further, the fixing bracket 12 includes the ribs 12 a as well as the ribs 12 b welded substantially perpendicularly to the ribs 12 a. For this reason, the rigidity of the fixing bracket 12 can be improved, thereby reliably locking the socket 16.

Although the fixing brackets 12 for supporting the wire rope 14 are individually provided in the present embodiment, one circular tube or circular arc-shaped fixing bracket, which is provided continuously in the circumferential direction, can support the plurality of wire ropes 14.

Although the wire rope 14 is described as an example of the tensile member, the present invention is not limited to this case, and as long as it is stretched between the supporting parts with a tensile force, the tensile member may be, for example, parallel linear cables, a spiral rope, a strand rope, a PWS, a locked coil rope, a carbon fiber cable, a steel wire, a pipe, or a bar.

Second Embodiment

FIG. 7 shows a fixing bracket used in a tower in accordance with a second embodiment of the present invention. The same members as those in the above-mentioned embodiment are denoted by the same reference symbols and redundant description thereof is not repetitively provided.

In the present embodiment, the fixing bracket 12 d has a groove 20 for inserting the wire rope 14 thereinto. The groove 20 extends substantially linearly outward in the radial direction (toward the left in FIG. 7) from a free end of the fixing bracket 12 d (inner circumferential end in cross section of the tower; right end in FIG. 7), and terminates substantially at the center of the fixing bracket 12 d. A width of the groove 20 is substantially constant in the extending direction and is larger than a diameter of the wire rope 14. However, the width of the groove 20 is smaller than a width of a socket base 16 a serving as a base of the socket 16, and by provision of the groove 20, the socket 16 is locked without passing through the fixing bracket 12 d.

FIG. 8 is a bottom view of the fixing bracket 12 d. The ribs 12 b are provided so as not to block the groove 20.

With the above-mentioned configuration, the present embodiment has the following effects.

Even in the state where the end of the wire rope 14 is provided with the socket 16, by sliding the wire rope 14 along the groove 20 from the free end of the fixing bracket 12 d outward in the radial direction (from the right to the left in FIG. 7), the socket 16 can be locked with the fixing bracket 12 d. That is, the wire rope 14 and the socket 16 can be previously joined to each other in a plant or the like so as to have a sufficient strength against the tensile force, and a task of connecting the wire rope 14 to the socket 16 on a construction site of the tower is not required.

Third Embodiment

FIG. 9 shows a fixing bracket used in a tower in accordance with a third embodiment of the present invention. The same members as those in the above-mentioned embodiments are denoted by the same reference symbols and redundant description thereof is not repetitively provided.

In the present embodiment, the socket 16 is rectangular in a plan view, specifically, oblong. A through hole 22 for inserting the wire rope 14 thereinto is formed in the fixing bracket 12 e. The through hole 22 is oblong like the socket 16 and has a dimension that enables insertion of the socket 16.

A concave part 22 a dented in the plate thickness direction is provided in an upper surface of the fixing bracket 12 e. The concave part 22 a is in an oblong shape that is slightly larger than the socket 16 in a plan view, and the socket 16 is partially or entirely fitted into the concave part 22 a. A long side of the oblong concave part 22 a is shifted from a long side of the oblong through hole 22 in the rotational direction, and is shifted by 90 degrees in the present embodiment. That is, in the present embodiment, the concave part 22 a and the through hole 22 form a substantially cross shape in a plan view. When the wire rope 14 is locked with the fixing bracket 12 e, the socket 16 is fitted into the concave part 22 a.

In FIG. 10, the ribs 12 a and the ribs 12 b are arranged so as to surround the through hole 22.

With the above-mentioned configuration, the present embodiment has the following effects.

Even when the end of the wire rope 14 is provided with the socket 16, it is possible to pass the socket 16 into the fixing bracket 12 e through the through hole 22 and insert the wire rope 14 into the fixing bracket 12 e. Then, after insertion, the socket 16 is rotated to fit the bottom of the socket 16 into the concave part 22 a for fixation. As described above, the wire rope 14 and the socket 16 can be previously joined to each other in a plant or the like so as to have a sufficient strength against the tensile force, and the task of connecting the wire rope 14 and the socket 16 on a construction site of the tower is not required.

Since the socket 16 is partially or entirely fitted into the concave part 22 a, the socket 16 can be prevented from freely rotating on the fixing bracket 12 e and passing through the through hole 22.

The ribs 12 a and the ribs 12 b can be arranged so as to surround the through hole 22. By providing the ribs 12 a and the ribs 12 b in this manner, the rigidity of the fixing bracket 12 e can be improved.

Fourth Embodiment

FIG. 11 shows a fixing bracket used in a tower in accordance with a fourth embodiment of the present invention. The same members as those in the above-mentioned embodiments are denoted by the same reference symbols and redundant description thereof is not repetitively provided.

In the present embodiment, a shim 24 is arranged between the socket 16 and a fixing bracket 12 c. The thickness of the shim 24 can be appropriately selected.

With the above-mentioned configuration, the present embodiment has the following effects.

By inserting the shim 24 between the socket 16 and the fixing bracket 12 c, the extension distance of the wire rope 14 can be changed. That is, the wire rope 14 can be stretched with a predetermined tensile force. Since the thickness of the shim 24 can be appropriately selected, even when the position of the fixing bracket 12 c or the shape of the tower section 2 varies, the wire rope 14 can be stretched with a predetermined tensile force.

Since the wire rope 14 can be stretched with the predetermined tensile force even when the position of the fixing bracket 12 c or the shape of the tower section 2 varies, manufacturing costs of the tower in the above-mentioned configuration can be reduced.

Fifth Embodiment

FIG. 13 shows a fixing bracket 12 f used in a tower in accordance with a fifth embodiment of the present invention. The same members as those in the above-mentioned embodiments are denoted by the same reference symbols and redundant description thereof is not repetitively provided.

In the present embodiment, the fixing bracket 12 f has a through hole 25. A female screw part is provided in an inner circumferential surface of the through hole 25, and the socket 16 has a displacement adjusting part 16 c screwed into the female screw part.

The sectional shape of the socket base 16 a on a plane perpendicular to the axis of the wire rope 14 is a polygon such as a hexagon having width across flats.

With the above-mentioned configuration, the present embodiment has the following effects.

The sectional shape of the socket base 16 a on the plane perpendicular to the axis of the wire rope 14 is a polygon, and thus, when rotating about the axis of the wire rope 14, the socket 16 is less likely to slip and can be easily rotated. By rotating the socket 16 to advance or retreat, in the stretching direction of the wire rope 14, the displacement adjusting part 16 c of the socket 16 screwed into the female screw part provided in the inner circumferential surface of the through hole 25, the extension distance of the wire rope 14 can be changed. That is, since the wire rope 14 can be stretched with a predetermined tensile force even when the position of the fixing bracket 12 c or the shape of the tower section 2 varies, manufacturing costs of the tower in the above-mentioned configuration can be reduced.

Sixth Embodiment

FIG. 14 shows a fixing bracket 12 g used in a tower in accordance with a sixth embodiment of the present invention. The same members as those in the above-mentioned embodiments are denoted by the same reference symbols and redundant description thereof is not repetitively provided.

In the present embodiment, the socket base 16 a has a plurality of socket threaded holes 16 e each provided with a female screw part in an inner circumferential surface. A bolt 30 is screwed into each of the socket threaded holes 16 e.

A recess 12 h for inserting a tip end (lower end in the figure) of the bolt 30 is provided in an upper surface of the fixing bracket 12 g in contact with the tip end of the bolt 30.

With the above-mentioned configuration, the present embodiment has the following effects.

By rotating the bolt 30 to advance or retreat the socket 16 with respect to the bracket 12 g, the position of the socket 16 relative to the fixing bracket 12 g can be adjusted. That is, the extension distance of the wire rope 14 can be changed. Accordingly, since the wire rope 14 can be stretched with a predetermined tensile force even when the position of the fixing bracket 12 c or the shape of the tower section 2 varies, manufacturing costs can be reduced.

In addition, since the recess 12 h is provided at the contact part of the bolt 30 with the fixing bracket 12 g, the socket 16 can be prevented from rotating with respect to the fixing bracket 12 g.

Seventh Embodiment

FIG. 15A and FIG. 15B each show a fixing bracket 12 c used in a tower in accordance with a seventh embodiment of the present invention. The same members as those in the above-mentioned embodiments are denoted by the same reference symbols and redundant description thereof is not repetitively provided.

In the present embodiment, a jack 32 is provided on the fixing bracket 12 c. The jack 32 is configured to adjust the position of the socket 16 with respect to the fixing bracket 12 c.

The jack 32 has a shaft 34 for operating the jack 32. As shown in FIG. 15B, the jack 32 is arranged at an offset position so as not to interfere with the wire rope 14.

With the above-mentioned configuration, the present embodiment has the following effects.

By providing the jack 32 and rotating the shaft 34, the position of the socket 16 with respect to the fixing bracket 12 c can be adjusted. That is, the extension distance of the wire rope 14 can be changed, and since the wire rope 14 can be stretched with a predetermined tensile force even when the position of the fixing bracket 12 c or the shape of the tower section 2 varies, manufacturing costs of the tower in the above-mentioned configuration can be reduced.

Eighth Embodiment

FIG. 16 shows a wire jack 36 used in a tower in accordance with an eighth embodiment of the present invention. The same members as those in the above-mentioned embodiments are denoted by the same reference symbols and redundant description thereof is not repetitively provided.

In the present embodiment, the wire jack 36 is provided at a middle of the wire rope 14. A wire stop 40 is fixedly arranged at a one end (upper end in this figure) of the wire rope 14. The wire stop 40 is locked to a wire jack body 38, and the wire stop 40 and the wire rope 14 connected thereto freely rotate with respect to the wire jack body 38. A wire stop 42 is provided at another end (lower end in this figure) of the wire rope 14. A jack screw part 44 is provided on the wire stop 42. The jack screw part 44 is screwed into a threaded hole of the wire jack body 38.

With the above-mentioned configuration, the present embodiment has the following effects.

The wire jack 36 provided at a middle of the wire rope 14 can adjust the tensile force of the wire rope 14.

Accordingly, since the wire rope 14 can be stretched with a predetermined tensile force even when the position of the fixing bracket or the shape of the tower section 2 varies, manufacturing costs of the tower in the above-mentioned configuration can be reduced.

Ninth Embodiment

FIG. 17A and FIG. 17B each show a tower in accordance with a ninth embodiment of the present invention. The present embodiment is different from the first embodiment in that the wire rope 14 is arranged to pass through a plurality of paired flanges. The same members as those in the above-mentioned embodiments are denoted by the same reference symbols and redundant description thereof is not repetitively provided.

As shown in FIG. 17A, the tower 3 is shaped into a frustum of circular cone and the fixing bracket 12 is provided at the uppermost tower section 2 among the tower sections 2 constituting the tower 3. The socket 16 is locked to the fixing bracket 12.

FIG. 17B shows arrangement and the like of the wire ropes 14 stretched using the sockets 16 and the fixing brackets 12 connecting the wire rope 14 to the tower section 2. By interposing the tower section 2, to which the fixing bracket 12 is not attached, between the tower sections 2 to each of which the fixing bracket 12 is attached, and applying the tensile force of the wire rope 14 between the upper and lower fixing brackets 12, the plurality of tower section 2 are integrally fixed.

With the above-mentioned configuration, the present embodiment has the following effects.

Since the number of the fixing brackets 12 used for connecting the plurality of tower sections 2 can be minimized, construction costs and manufacturing costs can be reduced.

Tenth Embodiment

FIG. 18 shows a tower in accordance with a tenth embodiment of the present invention. The same members as those in the above-mentioned embodiments are denoted by the same reference symbols and redundant description thereof is not repetitively provided.

An eye (supporting part) 46 is provided at the uppermost tower section 2 among the tower sections 2 constituting the tower shaped into a frustum of circular cone in the present embodiment. One end of the wire rope 14 is fixed to the eye 46, while another end is fixed by the socket 16 locked to the fixing bracket (supporting part)12 that is provided on the tower base B. In this manner, the wire rope 14 is stretched by the eye 46 and the socket 16.

With the above-mentioned configuration, the present embodiment has the following effects.

Since the number of the fixing brackets 12 used for connecting the plurality of tower sections 2 can be minimized, construction costs and manufacturing costs can be reduced.

The tower and the wind turbine generator according to the present invention can be appropriately changed, without being limited to the above-mentioned embodiments, within the scope of the concept of the present invention. The embodiments of this application can be also used in combination as appropriate. 

What is claimed is:
 1. A tower including a plurality of tower sections formed by dividing the tower along a plurality of planes that are substantially parallel to a horizontal plane, the tower being constituted by connecting end surfaces of the tower sections to each other, the tower comprising: a tensile member that has one end supported by a first supporting part arranged at a first tower section among the plurality of tower sections, that has another end supported by a second supporting part arranged at a second tower section among the plurality of tower sections or at a tower base on which the tower is vertically installed, and that is stretched along an inner wall of the tower sections so as to have a predetermined tensile force.
 2. The tower according to claim 1, wherein the tensile member is a wire rope.
 3. The tower according to claim 1, wherein each of the end surfaces of the tower sections serves as a flange surface of an inner flange protruding toward a center in cross section of the tower section, a shearing bolt or a shearing key is fitted into each of a plurality of holes formed substantially vertically in the flange surface, and relative positions between the flanges are fixed.
 4. The tower according to claim 1, wherein a mechanism adapted to adjust an axial length of the tensile member is provided at a middle of the tensile member.
 5. The tower according to claim 1, wherein the tensile member is stretched in a substantially vertical direction, at least one of the first supporting part and the second supporting part includes a groove or a through hole into which the tensile member is inserted, a socket is fixedly attached to an end of the tensile member, the end corresponding to the groove or the through hole, and the socket is locked to the supporting part, to restrict displacement with respect to the supporting part.
 6. The tower according to claim 5, wherein the socket includes a mechanism adapted to adjust relative positions between the socket and the supporting part.
 7. The tower according to claim 5, wherein the first supporting part and/or the second supporting part includes a first member located on a side where the socket is arranged and a second member located on a side opposite to the socket with the first member being interposed therebetween, and the second member supports the first member and is connected to an inner wall surface of the tower section.
 8. A wind turbine generator comprising the tower according to claim
 1. 